JP2010116897A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil for an internal combustion engine for securing the sure electric connection between a terminal pin and a high pressure terminal. <P>SOLUTION: This ignition coil for the internal combustion engine is constituted so that a plate spring 9 as a substantially guitar-shaped conductive elastic body having an opening part 91 and a narrow press-in part 92, is continuously arranged on the high pressure terminal 7, and the terminal pin 41 of a secondary coil 4 is pressed in and fixed to the opening part 91 of the plate spring 9, and the plate spring 9 intermediates in the electric connection between the terminal pin 41 of a terminal part of the secondary coil 4 and the high pressure terminal 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ignition coil for an internal combustion engine that supplies a high voltage for generating spark discharge in an ignition plug of an engine such as an automobile, for example, and ensures electrical connection between a terminal portion of a secondary coil and a high-voltage terminal. The present invention relates to an ignition coil for an internal combustion engine that meets the expectation of reliability improvement.

  Conventionally, the connection between the terminal portion of the secondary coil and the high voltage terminal in the ignition coil for an internal combustion engine has been established by pressure welding utilizing the elasticity of each component. Specifically, the terminal portion of the secondary coil is a wire-shaped terminal pin, and its tip is extended to the high-pressure cylinder portion provided in the insulating case and pressed against the high-voltage terminal accommodated in this high-pressure cylinder portion. It was.

  In such an ignition coil for an internal combustion engine, when the internal temperature rises during operation and a thermal stress is generated in the insulating resin filled in the insulating case, this thermal stress acts in a direction to cut off the contact between the terminal pin and the high-voltage terminal. In this case, there is a problem that poor conduction occurs.

Therefore, an invention aimed at securing an electrical connection by providing a terminal pin holding portion on a secondary coil bobbin around which a secondary coil is wound and pressing the terminal pin against a high voltage terminal by the terminal pin holding portion is as follows. This is proposed in Patent Document 1.
JP 2008-135494 A

  As shown in FIG. 4, the ignition coil 10 for an internal combustion engine in the invention according to Patent Document 1 includes a primary coil 12 in which an electric wire is wound around a primary coil bobbin 11, and an electric wire wound around a secondary coil bobbin 13. The insulating case 16 provided with the secondary coil 14, the iron core 15 that magnetically couples the secondary coil 14 and the primary coil 12, and the high-voltage cylinder portion 161 that accommodates the high-voltage terminal 18 in the lower part. In particular, as shown in FIG. 5, the secondary coil bobbin 13 has a flange portion 13 a extending to form a terminal pin holding portion 19, and the terminal portion of the secondary coil 14 is connected to a wire-like terminal pin. 17, the terminal pin 17 is pressed against the high-voltage terminal 18 by the terminal pin holding part 19, so that the terminal pin 17 is reliably brought into contact with the high-voltage terminal 18 by the terminal pin holding part 19. Bets can be, a conduction failure due to thermal stress of the insulating resin generated during operation of the ignition coil becomes what can be prevented.

  However, there is a universal demand for improving the reliability of the ignition coil for an internal combustion engine, and the terminal pin 17 and the high-voltage terminal 18 are connected by pressure contact or pressing as in Patent Document 1 (FIG. 4 or FIG. 5). On the extension line of the conventional technical idea, there is a problem that the possibility that a conduction failure occurs due to some cause cannot be completely avoided.

  The present invention has been proposed in view of the above circumstances, and has created a new technology for connecting the terminal pin, that is, the terminal portion of the secondary coil and the high-voltage terminal, and specifically, the structure of the high-voltage terminal. An object is to provide an ignition coil for an internal combustion engine that can be devised to ensure electrical connection between the terminal portion of the secondary coil and the high-voltage terminal and meet the expectation of improved reliability.

  In order to achieve the above object, the present invention includes a primary coil, a secondary coil, a housing part that houses the secondary coil and an iron core that is magnetically coupled to the primary coil, and a housing part that extends outward from the housing part. Each of these components is housed in an insulating case provided with a cylindrical high-voltage cylinder portion that accommodates a high-voltage terminal to which a terminal portion of the secondary coil is connected, and filled with an insulating resin. In the ignition coil for an internal combustion engine, a substantially bowl-shaped conductive elastic body having an opening and a narrow press-fit portion is connected to the high-voltage terminal, and the end of the secondary coil is connected to the press-fit portion of the conductive elastic body. A portion is press-fitted and fixed, and the conductive elastic body mediates connection between the terminal portion of the secondary coil and the high-voltage terminal.

  In particular, it is preferable that the high-voltage terminal includes a protrusion that positions a terminal portion of a secondary coil that penetrates a part of the conductive elastic body and is fixed at the press-fitting portion.

  The conductive elastic body is more preferably a leaf spring obtained by processing phosphor bronze.

  In the ignition coil for an internal combustion engine according to the present invention, a substantially bowl-shaped conductive elastic body having an opening and a narrow press-fit portion is connected to a high-voltage terminal, and the end of the secondary coil is connected to the press-fit portion of the conductive elastic body. The parts are press-fitted and fixed, and the conductive elastic body mediates the connection between the end of the secondary coil and the high-voltage terminal, so the thermal stress generated when the ignition coil operates, vibration during engine operation, and insulation Connection between the terminal portion of the secondary coil and the high-voltage terminal is not disconnected based on the inconvenience when filling the resin, that is, there is no conduction failure, and the terminal portion of the secondary coil and the high-voltage terminal Can be ensured.

  In particular, the high-voltage terminal includes a protrusion that positions a terminal portion of the secondary coil that penetrates a part of the conductive elastic body and is fixed by the press-fitting portion. Is accurately positioned in the press-fit portion of the conductive elastic body, so that the end portion of the secondary coil is securely fixed to the press-fit portion, and the end portion of the secondary coil and the high-voltage terminal are Can be ensured.

  Furthermore, since the conductive elastic body is a leaf spring obtained by processing phosphor bronze, the end portion of the secondary coil is firmly fixed to the press-fit portion of the leaf spring, and the thermal stress of the insulating resin generated during operation of the ignition coil, The connection between the terminal part of the secondary coil and the high voltage terminal is surely lost due to vibration during engine operation, inadequate filling with insulating resin, etc. It becomes possible to prevent the continuity failure and the like in between.

  That is, according to the present invention, the electrical connection between the terminal portion of the secondary coil and the high voltage terminal in the ignition coil for the internal combustion engine is performed by using a substantially bowl-shaped conductive elastic body having an opening and a narrow press-fitting portion. It is connected to the terminal, and the terminal portion of the secondary coil is press-fitted and fixed to the press-fitted portion of the conductive elastic body, and is mediated by the conductive elastic body. In particular, the high-voltage terminal is connected to the conductive elastic body. The terminal of the secondary coil is provided with a protrusion that positions a terminal part of the secondary coil that penetrates a part and is fixed at the press-fitting part, and the conductive elastic body is a leaf spring processed with phosphor bronze. Is firmly fixed to the press-fitted portion of the leaf spring, and the fixing is performed after the positioning is accurately performed by the protrusion of the high voltage terminal, and the connection between the leaf spring and the high voltage terminal is also reliably performed. Prevents poor conduction between the terminal of the secondary coil and the high-voltage terminal. It is possible to provide an internal combustion engine ignition coil capable.

Hereinafter, an embodiment illustrating an ignition coil for an internal combustion engine according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic longitudinal sectional view of an ignition coil for an internal combustion engine according to the present invention, FIG. 2 is an enlarged sectional view of a main part of FIG. 1, and FIG. 3 is an ignition coil for an internal combustion engine according to another embodiment. It is a schematic longitudinal cross-sectional view. The same or corresponding parts as those in the ignition coil for the internal combustion engine shown as the conventional example in FIGS.

  As shown in FIG. 1, the ignition coil for an internal combustion engine according to the present invention includes a primary coil 2, a secondary coil 4, an iron core 5 that magnetically couples these two coils, and a power switch 3 that is an accommodating portion 61 of an insulating case 6. Is housed in. Moreover, the high voltage terminal 7 to which the terminal pin 41 as the terminal portion of the secondary coil 4 is connected is connected to the cylindrical high voltage cylinder portion 62 that is connected to the outside, for example, downward. Contained. Insulating case 6 in which these components are accommodated is filled with insulating resin 8 and each component is fixedly held. In particular, in the ignition coil 1 for an internal combustion engine according to the present invention, a plate spring 9 as a substantially bowl-shaped conductive elastic body having an opening 91 and a narrow press-fitting portion 92 is connected to the high-voltage terminal 7. The terminal pin 41 of the secondary coil 4 is press-fitted and fixed to the press-fit portion 91 of the leaf spring 9, thereby mediating the electrical connection between the terminal pin 41 of the secondary coil 4 and the high-voltage terminal 7.

  The substantially saddle-shaped leaf spring 9 is made of, for example, phosphor bronze, and has an opening 91 and a narrow press-fit portion 92 as shown in FIG. Specifically, the opening 91 is formed by bending the leaf spring 9 and expanding both tip portions upward. Further, the narrow press-fitting portion 92 is formed by further bending the center portions of the opposed side walls formed by bending the leaf spring 9 in the direction of contact.

  As shown in FIG. 2, the high-voltage terminal 7 has a protruding portion 71 that penetrates a part of the bottom surface portion 93 of the leaf spring 9 at the upper end portion. The tip 71a of the projecting portion 71 is located at the press-fit portion 92 of the leaf spring 9. When the terminal pin 41 of the secondary coil 4 is press-fit into the press-fit portion 92 of the leaf spring 9, the tip 71a functions to determine its position. Yes. The lower end of the high voltage terminal 7 is electrically connected to the spark plug via the conductive spring A and the noise preventing resistor B.

  Here, how to reliably connect the terminal pin 41 of the secondary coil 4 and the high voltage terminal 7 in the ignition coil 1 for an internal combustion engine according to the present invention will be described with reference to FIG.

First, various components are accommodated in predetermined positions in the accommodating portion 61 of the insulating case 6, and then the terminal pin 41 of the secondary coil 4 is arranged near the high-pressure cylinder portion 62 of the insulating case 6 as shown in FIG. 2. Set up. Next, the protruding portion 71 of the high-voltage terminal 7 is inserted through a part of the bottom surface portion 93 of the substantially bowl-shaped plate spring 9, and the plate spring 9 is connected to the high-voltage terminal 7. At this time, the protrusion 71 of the high-voltage terminal 7 is continuously inserted until the tip 71 a of the protrusion 71 of the high-voltage terminal 7 is positioned at the press-fit portion 92 of the leaf spring 9.
Further, the plate spring 9 connected to the high voltage terminal 7 is inserted together with the high voltage terminal 7 from the lower side of the high voltage cylinder part 62 of the insulating case 6 to the high voltage cylinder part 62 with the opening 91 of the plate spring 9 facing upward. The terminal pin 41 of the secondary coil 4 is press-fitted into the press-fitting portion 92 of the leaf spring 9.

Then, the terminal pin 41 of the secondary coil 4 is guided to the press-fit portion 92 along the side wall of the substantially saddle-shaped leaf spring 9, and further, the press-fit portion 92 has a bottom surface portion 93 of the leaf spring 9 of the high-voltage terminal 7. While being positioned by the tip 71a of the protruding portion 71 penetrating partly, it is firmly fixed to the narrow press-fit portion 92 of the leaf spring 9. That is, the connection between the leaf spring 9 and the terminal pin 41 of the secondary coil 4 can be easily performed due to thermal stress of the insulating resin generated when the ignition coil is operated, vibration during engine operation, inadequate filling of the insulating resin, and the like. The terminal pin 41 of the secondary coil 4 and the leaf spring 9 are reliably electrically connected without being disconnected. Further, the leaf spring 9 is also electrically connected to the high voltage terminal 7 through the bottom surface portion 93 connected to the high voltage terminal 7 or through the protrusion 71 of the high voltage terminal 7.
Thereafter, the high voltage terminal 7 is electrically connected to the spark plug via the conductive spring A and the noise prevention resistor B, so that the terminal pin 41 of the secondary coil 4 and the high voltage terminal 7 as in the present invention are used. An ignition coil 1 for an internal combustion engine that can reliably prevent a conduction failure between and the like is assembled.

  Therefore, in the ignition coil 1 for an internal combustion engine according to the present invention, the substantially saddle-shaped plate spring 9 having the opening 91 and the narrow press-fit portion 92 is connected to the high-voltage terminal 7, and the bottom portion 93 of the plate spring 9 is provided. The terminal pin 41 of the secondary coil 4 is press-fitted into the press-fitting portion 91 of the leaf spring 9 while positioning the terminal pin 41 of the secondary coil 4 at the tip 71a of the protrusion 71 of the high-voltage terminal 7 that penetrates a part of The terminal pin 41 of the secondary coil 4 is press-fitted into the leaf spring 9 since the electrical connection between the terminal pin 41 of the terminal portion of the secondary coil 4 and the high voltage terminal 7 is mediated by the leaf spring 9. It is firmly fixed to the portion 92, and the fixing is also accurately positioned by the protrusion 71 of the high-voltage terminal 7, so that an electrical connection is made, and the bottom surface portion 93 connected to the high-voltage terminal 7. Or through the protrusion 71 of the high-voltage terminal 7 Since the electrical connection between the terminal 9 and the high-voltage terminal 7 is also performed reliably, it is possible for an internal combustion engine that can reliably prevent poor conduction between the terminal pin 41 of the secondary coil 4 and the high-voltage terminal 7. An ignition coil 1 can be provided.

  Here, the ignition coil for an internal combustion engine according to the present invention is different from the above-described embodiment even in another embodiment configured by removing the noise prevention resistor from the constituent article in the above-described embodiment as shown in FIG. Similar effects can be obtained. That is, in the present invention, the terminal pin of the secondary coil is firmly fixed to the press-fit portion of the leaf spring, and the fixing is performed after being accurately positioned by the protrusion of the high-voltage terminal. The terminal pin is fixed to the press-fitted portion of the leaf spring, so that it is possible to reliably prevent poor conduction between the terminal pin of the secondary coil and the high voltage terminal. To provide an ignition coil for an internal combustion engine that eliminates the need to consider occurrence and does not require a noise prevention resistor to distribute a high voltage from a high-voltage terminal to an ignition plug, and is advantageous in terms of cost. Can do.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example. The present invention can be modified in various ways without departing from the scope of the claims.

  The present invention can also change the shape of the ignition coil for an internal combustion engine without departing from the matters described in the claims. Needless to say, the materials used for the components of the ignition coil for an internal combustion engine of the present invention may be known or known materials.

It is a schematic longitudinal cross-sectional view of the ignition coil for internal combustion engines which concerns on this invention. It is a principal part expanded sectional view of FIG. It is a schematic longitudinal cross-sectional view of the ignition coil for internal combustion engines which concerns on other embodiment. It is a longitudinal cross-sectional view which shows the relationship between the high voltage terminal and the terminal pin in the conventional ignition coil for internal combustion engines. It is a principal part expanded sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil for internal combustion engines 2 Primary coil 3 Power switch 4 Secondary coil 41 Terminal pin 5 Iron core 6 Insulating case 61 Housing part 62 High pressure cylinder part 7 High voltage terminal 71 Projection part 71a Tip 8 Insulating resin 9 Leaf spring (conductive elastic body )
DESCRIPTION OF SYMBOLS 91 Opening part 92 Press-fit part 93 Bottom face part A Spring B Noise prevention resistance 10 Conventional ignition coil for internal combustion engine 11 Primary coil bobbin 12 Primary coil 13 Secondary coil bobbin 13a ridge part 14 Secondary coil 15 Iron core 16 Insulating case 161 High pressure cylinder part 17 terminal pin 18 high voltage terminal 19 terminal pin holding part

Claims (3)

A primary coil, a secondary coil, a housing part in which an iron core that is magnetically coupled to the secondary coil and the primary coil is housed, and a terminal part of the secondary coil that is connected to the outside from the housing part. In an insulating case having a cylindrical high-pressure cylinder portion that accommodates a high-voltage terminal to be connected, each of these components is accommodated and filled with an insulating resin.
A substantially bowl-shaped conductive elastic body having an opening and a narrow press-fit portion is connected to the high-voltage terminal, and the end of the secondary coil is press-fitted and fixed to the press-fit portion of the conductive elastic body. In the conductive elastic body, the connection between the terminal portion of the secondary coil and the high-voltage terminal is mediated,
An ignition coil for an internal combustion engine. The high-voltage terminal includes a protrusion that positions a terminal portion of the secondary coil that penetrates a part of the conductive elastic body and is fixed at the press-fit portion.
The ignition coil for an internal combustion engine according to claim 1. The conductive elastic body is a leaf spring obtained by processing phosphor bronze.
The ignition coil for an internal combustion engine according to claim 1 or 2, characterized by the above.

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